Product Design: Allen Key Holder (Part 1)

Isometric view of the finished product in Solidworks.

For my first real design project I was given a problem, solve an issue by creating a simple design with mechanical properties. I chose to design an allen key holder because allen keys are always getting lost, and they're a pain to hold when you're working. At first I had a very basic design, but the project proved to be more challenging than I originally expected. I started with a flat oval shaped 2-D holder, I slowly made changes and improvements from there.

The first real change, oval shaped to rectangle.

The first change I made was going from an oval shaped holder, to a rectangle. I felt the change was necessary, an oval is an obscure shape and harder to build off of than a rectangle.

Frontal view of the first 3-D model.

Inside view of the first 3-D model.

The next change I made was to go from a 2-D model to a 3-D model. At first I assumed the allen keys would be able to hang in place, so a 2-D model seemed reasonable. I realized my ideas worked better on paper and that it was time to improve. At first I only made the holder 3-D, but doing this still didn't solve my issue of the allen keys falling out.

Frontal view after changing from the large bulky rectangular box.

After making the holder 3-D, I decided it was too bulky and wasn't optimal in working conditions, so I reverted back to original flat 2-D holder. Rather than making the holder bulky, all I needed was a small frame and a door to hold the allen keys in place. This is also the point where I started designing the hinges, as you can see I started out with just scraps of paper.

After adding the latch and hinges. (closed)

I was originally going to make the hinges resemble door hinges, but I realized there would be no way to assemble it. The way a door hinge is made, is by sliding a long cylinder in between tubes, and then flattening the end so it won't slide out. There would be no way to flatten it with  my design, so I switched to watch pins which are meant to clip in.

Frontal view of the holder after the belt clip was attached.

As you can see in the pictures above, the latch was simple. I attempted using other locking mechanisms but this one worked the best. One other thing that is very noticeable in the image above, is the durability of the materials. At this stage of design, the cardboard was starting to separate and tear. However, there was benefits to this, it showed me what areas of the holder were the weakest, and that might break even on a model of stronger material. This is when I decided to cut off the handle. The handle I'm referring to is the thin piece at the very top of the design with copper wire bent around it.

After cutting off the handle.

From this point I did most of my design in Solidworks. The physical model was only missing the clip for attaching it to a belt, but it was starting to fall apart where it was glued. The belt clip was simple to make, I started by making a rectangle and cutting a slot out of it for the belt. Then I just rounded out the edges, so it wouldn't cut anyone when made out of harder material. From here I made small improvements on the design.

Before rounding the hinges.

After rounding the hinges.

Working in Solidworks I was able to make improvements that were near impossible when working with cardboard. For example, I made the hinges lie flush with the door, and rounded them out so the door wouldn't clip them.

I've been asked a lot of questions while designing this so I thought it would be appropriate to compile a general Q & A section.

Q: Was the physical model hard to make?

Left side view of the handle bending.

A: No, the physical model was easy to make once I had a design in mind. I ran through a few ideas before I decided to stick with the one I have now. However an issue that I constantly struggled with was the durability of the materials. I used cardboard and copper wire to make the physical model and the cardboard didn't always hold up so well. The copper wire snapped easily and would sometimes destroy the cardboard being that it is a harder material. In the photo above you can see how the handle was tearing and bending.

Q: What made you want to design an allen key holder?

Original hinge concept design, drawn by Mr. Grosinger.

A: Well, I wanted to keep the project reasonably simple, and having experience in electrical work, I remembered how annoying it was to hold small allen keys as you climb up a ladder, especially if you need other tools. I was also told this would be a great first project by my teacher Mr. Grosinger.

Q: How different was your first model from the final design?

A: My first model was immensely different from my last. The first model was an oval shaped holder, with no way to secure the allen keys in place. It was a flat piece of cardboard and the allen keys basically just hung in place, and would easily fall out. Slowly, I started adding on bits and pieces until I got to the model you see now.

Q: So, What made you change your original design?

A: I started by sketching out my idea on paper. While I was trying to convert it into a physical model, it became apparent that the idea seemed to work on paper. On paper the design worked well, the allen keys stayed in place and it clipped onto a belt with no problem, all in a compact design I might add. In reality, the allen keys get pushed out of the holder just from walking, and this model was too flimsy.

Q: Okay, so the cardboard model revealed some flaws.  What changes did you make to correct this?

A: The first change I realized I had to make was, going from a 2-D to 3-D model, a flat piece of material wasn't going to cut it. Secondly, I needed something to hold the allen keys in place, without securing them they would fall out no matter what else I changed. Later on I made improvements, but these were really the only things that I changed.

Q: How did you secure the allen keys?

A: My first attempt at securing the allen keys was by adding clips on the back of the holder. I believed the short end of the allen keys would clip in and stay firmly in place, but the clips were extremely difficult to make out of cardboard. With the clips not working mechanically how I pictured them, I decided it was time to try a new design. This is when I started to design the door and latch, which ended up working exactly how I wanted it to. It left enough space so that it didn't put too much pressure and break the holder when the allen keys moved, but enough strength to hold them in place.

Q: What was you biggest challenge?

A failed attempt at 3-D printing the door.

A: My biggest challenge was 3-D printing the model I created in Solidworks. Part of the problem was design flaws like the hinges, but most of the issues came from the printer itself. As you can see above, the printer isn't perfect. In this case, the holder became snagged on the nozzle, it started to get dragged around with the nozzle, which ended up burning a hole through it.

Q: What other problems did you encounter while working with the 3-D printer?

Printing without a raft.

A: Another issue I had was detaching the actual piece, which is the red plastic section, from the raft, which is the white layer underneath. The raft was a necessary step in the design, without it the plastic wouldn't stay in place, it would move with the nozzle and could never properly form the correct shape. What you see above is what happened only seconds after I started trying to print it without the raft.

A third attempt at printing the door piece.

Better example of the piece bending.

The raft may have been a necessary piece but it was also causing complications. The piece I was attempting to print was a thin piece, which made it hard to detach from the raft without breaking or bending it. In the first picture above, the problem of the piece being dragged is very apparent, you can see how it was pushed during the printing process causing it to fail. . The second picture illustrates  how the part was bending when trying to detach it from the raft. I was able to detach a small piece in the upper left corner, but the rest was stuck together and proved too difficult to detach without breaking the part.


Q: Once you make a 3-D plastic printed prototype, how do you plan to test it in a real world scenario?

A: I plan to take my 3-D printed model with me to work over the summer. I will be working in the electrical field again, over this two month period I will see how my design holds up.

To be continued...

A "Call Bell", mesaured and recreated in Solidworks

Joseph Piekut: This is the first real object I measured and rebuilt in Solidworks

Q: You said this is your first real object that you measured and created into SolidWorks... So, what is this object? It looks like a bell.

Side view of the final assembly.

Joseph: Yes, it is a bell, a "Call Bell" to be specific.

Q: Why did you chose a bell for your first project?

Photo of the actual bell used for this project.

Joseph: I chose this bell because it looked like a difficult project that would pose some challenges along the way, and I was limited to a project of five parts or less.

Q: Really? What could be challenging or difficult about creating a bell?

Isometric view of the clapper.

Joseph: For one, some parts didn't have specific measurements or shapes, for example, the "clapper" (the part that actually rings the bell) wasn't a perfect rectangle, it had odd cuts in the center so I had to improvise to get it as close as possible.

Q: How do you measure the parts?

Picture of the caliper I used for this project.

Joseph: Good question, I measured all of the parts for this project using a tool called a caliper. It provides measurements that are more accurate than a ruler, specifically measurements up to a thousandth of an inch (or the third decimal place in a number). Just imagine a human hair is .002 of an inch.

Q: Cool, what else was a challenge?

The bolt that the button/pin rests in to hold it in place between the bracket and the shell.

Joseph: Another piece that gave me a bit of a challenge at first was, the bolt that holds the button/pin piece in place. It has multiple shapes directly on top of one another. Some of the shapes couldn't be simply extruded, they had to be carefully sketched and then edited even after extruding or lofting them.

Q: Slow down, what do you mean "extruding or lofting"?

Here is an example of an extrution from a hexagon.

Joseph: An extrusion is when you take a flat 2D sketch and make it 3D by giving a thrid dimension, height.

Q: Oh, ok... Were there any moments when you got stuck and later it hit you how easy it really was?

Isometric view of the bracket piece.

Joseph: Yes actually, this piece shown above, the bracket gave me a lot of trouble at first, I stopped working on the piece and came back to it later when I realized how easy it was. Specifically the hooks on the front in the picture above. It was hard, I tried everything, or so I thought. I tried making new planes, sketching them out, drawing them from every angle. So you can imagine how frustrating it was. In the end all I had to do was create a plane in the center of the curved area and extrude a circle to both faces, this kept the extrude consistent with the curve of the piece. The next step was to cut a smaller circle out of the extruded circle and then just cut a slot so the clapper can slide into the hooks like on the physical bell.

Q: Wow...That is a lot of work. Can you show us what you mean?

Joseph: Here you can see on one side I have the extruded circle and on the opposite side I took the next step and cut out the smaller circle.

Q: You said there were slots that yout cut, where are they? How is the clapper supposed to get in there?

Side view of the bracket to better show off the hooks that hold the clapper.

Joseph: Above you can see the next step in the process of making these hooks, I had to cut out the slot so the prongs on the clapper could slide in.

Q: How does this fit wih the rest of the parts?

Shot to better show how the clapper fits into the bracket hooks.

Joseph: Above you can see how the clapper rests in the hooks, but still has freedom to swing forwards and ring the bell.

Q: Can you show us an exploded view of all the parts together?

Exploded view of the final assembly.

Joseph: Above you can see what the final assembly looks like as individual pieces and how they are assembled.

Q: Wow, that's a lot of work, did you put in this much effort on every part? What other parts did you make and how did you make them?
How It's Made

Isometric view of the metal shell that goes over the bracket.

Metal Bell

The metal bell was one of the easier parts I had to make for this project. It just required me to sketch half of the outline and then revolve that sketch around a center line.

Frontal view of the base part of the bell that the bracket attaches to.

Bell Base: Bottom (Without Bracket)

The bottom part of the base was easy enough. Same as the metal bell. A simple sketch with a revolved base and a few extruded cuts. The only part that took a bit of messing with, was the large center cut.  The ellipse shape didn’t look right. It couldn’t be a perfect circle. It just took some fiddling with. I added a spline and then I mirroried that spline a few more times.

Different view of the bracket piece.

Base Bracket

Simple sketch off of the front plane.   I wanted the top square to resemble that of the bracket on the physical piece. So I added extrudes like the one on the top. To make the hooks, I did a base extrude. After extruding, I had a large circle protruding from the bracket. I cut out the center circle, to leave only a ring. Finally, I cut the missing section from the hooks, so the clapper could slide into the hooks as if it were the physical model.

Isometric view of the base/bracket when assembled.

Side view of the base, bracket.

Bell Base: Complete

Here are a few pictures of the base. This was made from the base and bracket pieces.

Isometric view of the button or pin that you press to ring the bell.

Push Pin: Pin or Hammer Piece

This is the part that  pushes down onto the clapper to make the bell ring. It was a simple extruded circle, with a dome placed on the top. On the flat bottom side of that circle, I extruded another smaller circle to make the shaft of the pin. On the bottom of that pin, I sketched out the hammer looking part and extruded it. Unfortunately, I couldn’t get it to line up perfectly with the bottom of the shaft. It was hardly noticeable regardless, so I left it.

Bolt that holds the push pin.

Push Pin: Bolt

This is the bolt that holds the pin in place between the outside of the metal bell and the bracket.

Mainly just some extrudes combined with a lofted base for the sloped section right beneath the top sphere section. The top sphere was just a sketch with a revolved base. The bottom threads were just an extrude on a helix spiral.

Button/pin and bolt when assembled.

Push Pin: Complete

A view of the final assembly for the push pin and the bolt.

Side/frontal view of the clapper.

Clapper

This piece was a bit of a challenge at first, I sketched out a triangle for the pyramid shape. Then I cut out a section to separate the top like on the actual model. Next I smoothed out the correct edges using the fillet feature. Then from there I sketched out the body, off of that pyramid and extruded a rectangle. The unique shape comes from the cuts I made on it. This was done to mirror the physical model. The top face was fairly simple. I sketched some splines to curve it and then used the fillet to round out the top to my liking. To make the prongs I sketched directly on the side of the top face, and then used the fillet tool once again to round out the edges.

Thanks for reading my blog.
Joseph Piekut